This Shared Instrumentation Grant (SIG) application requests funds for the purchase of a state-of-the-art Becton-Dickinson FACSAria II cell sorter to be located in the Flow Cytometry Core Laboratory at the New Jersey Medical School. The FACSAria II cell sorter has numerous advantages over the 11 year-old, technologically outdated FACSVantage it will replace. Most importantly, the FACSAria II is a compact, desk- top sorter that can be placed in a Baker BioPROTect III class II biological safety cabinet, which is also requested in this proposal. The FACSAria II will be equipped with the aerosol management option for added operator protection. These features are essential to the majority of our users who need to sort either live human cells and cell lines or live, pathogen-infected cells, including HIV-infected cells;these projects cannot currently be carried out using the FACSVantage, which lacks these safety features. Additional features of the instrument that are necessary for our SIG investigators include four-way sorting, four lasers (355 nm (UV), 488 nm, 561nm and 640 nm) with the capability of detecting up to 14 parameters, a temperature control option for refrigeration and cooling of the pre- and post-sort samples, and an automatic cell deposition unit for desposition of fixed numbers of cells into plates or onto slides. The FACSAria has additional advantages over the FACSVantage that will benefit all of our users: it is faster and more efficient and its housing in the BioPROtect III will facilitate aseptic sorts. This application is supported by projects submitted by 10 major users and 9 minor users;the lasers and accessories were chosen to meet the sorting needs of this very diverse group of investigators. While a number of the investigators work in the area of infectious disease immunology, including, e.g., HIV immunology, parasite immunology, innate immunity, and cytokines, other investigators work in diverse areas such as cancer cell biology, stem cell biology, radiation biology, cardiovascular biology and lupus. This diversity in research interests is reflected in the fact that these SIG investigators are funded by six different institutes at the NIH: the NIAID, NCI, NIGMS, NIDDK, NHBLI and NIMH. All of these investigators extensively use flow cytometry in their studies, and nearly all have significant experience with sorting. There is strong institutional commitment to this FACSAria application: the medical school has committed ongoing funds for a full-time operator and service contract for the instrument. These costs will be offset, in part, by users fees from the SIG investigators and other investigators recruited to utilize this powerful technology. The FACSAria will be supported by a strong administrative structure including oversight by the Flow Cytometry Core Advisory Committee, which is chaired by the SIG PI, Dr. Fitzgerald-Bocarsly, who is also the Scientific Director of the Flow Cytometry and Immunology Core Laboratory. Overall, the introduction of this FACSAria II to our university community is expected to greatly enhance our investigators'productivity and contribution to biomedical science.